1. Field of the Invention
This invention relates to novel copolymerizable ultraviolet light absorber compounds, and, more particularly, to 4-allyloxybenzal-3'-alkyl-2'-benzothiazoazine compounds which are copolymerizable with vinyl monomers to provide polymer materials having improved resistance to degradation to light.
2. Description of the Prior Art
Various organic compounds exhibit the power to absorb electromagnetic radiation and can be incorporated in various plastic materials such as transparent sheets which act as filters for all the radiation passing through and will transmit only such radiations as are not absorbed by the sheet and/or the absorbing agent. Such filters find use in many technical and commercial applications.
Numerous cyano acrylic compounds have been suggested as absorbents for the range of radiations described above. For specific compounds, see U.S. Pat. Nos. 3,081,280; 3,272,810; 3,644,466; 3,256,312 and 3,215,724. These ultraviolet absorbers are mechanically mixed with the plastic materials to prevent discoloration and degradation of the material. However, it has been observed that such absorbers sometimes fail or are blocked out of the plastic under adverse weather conditions before the lifetime of the protected material. Also, it is not possible to use all of these ultraviolet absorbers with radiation curing of the plastic material. Another disadvantage of these ultraviolet absorbers is the high amount of absorber needed for protection of some materials.
Still another limitation on the use of the prior art absorbers is that they provide little or no protection in the 330 to 400 nm region, which is a desirable region when the absorbers are used for skin and hair care products, such as sunscreen preparations and hair dye and hair tinting compositions.
Accordingly, it is an object of the present invention to provide novel copolymerizable ultraviolet light absorber compounds which are substantially free of the disadvantages of the prior art.
A particular object of this invention is to provide novel compounds which can be copolymerized directly with monomers, such as plastic material, to provide more permanent ultraviolet light protection.
A specific object is to provide ultraviolet light absorber compounds containing a copolymerizable ethylenic group.
These and other objects and features of the invention will be made apparent from the following more particular description of the invention.